MORPHOLOGY OF LEUCOCYTES AND RED CORPUSCLES 221 



Method. — The patient is pricked, and the first drop of blood 

 wiped away as before. One of the half strips of cigarette-paper 

 is now held in the right hand, the index-finger being placed 

 above the strip, and the edges held between the thumb and 

 index-finger and the index and middle fingers respectively ; this 

 converts it into a gutter, the convex edge of which is downward. 

 The edge of this gutter which points away from you (and which 

 is formed by a machine-cut edge of the paper) is now dipped into 

 the drop of blood, and a small quantity picked up on its lower 

 surface. This lower surface is then placed on a clean slide 

 parallel to one of its shorter edges and about ^ inch from it, and 

 pressed gently upon it so as to flatten out the paper gutter ; as 

 this flattens out the edge of the drop of blood on its under surface 

 will follow it. The strip of paper is now drawn towards the other 



Fig. 49. — Method of spreading Films with Cigarette-paper. 



end of the slide with a steady uniform movement, and in doing so 

 the drop of blood is spread out into a long uniform film. In this 

 way a film \ inch wide and 2 inches long can be made on a single 

 slide. A fresh piece of paper is to be used for each specimen (see 

 Fig. 49). 



The author is of opinion that it is best to adopt the cover-glass 

 method, as he has found that it presents fewer difficulties for 

 beginners ; this' is not the universal experience, and it is a good 

 plan to try both, and adopt that with which you get the best 

 results. 



Films are sometimes spread on one slide by means of another, 

 which is used as a spreader in much the same way as the 

 cigarette-paper described above. This is very good for malaria 

 parasites, and for alterations in the red corpuscles, but is useless 

 for making differential counts, as some of the leucocytes are 

 carried along with the spreader and left at the end of the film. 



